https://userapps.support.sap.com/sap/support/knowledge/en/3446660
3446660 - Error "Field ZZ* in table MLREPEKPO is specified twice" during upgrade to S/4HANA | SAP...
During upgrade to S/4HANA or system upgrade process, in the ACT_UPG phase, an error is encountered that "Field ZZ* in table MLREPEKPO is specified twice".